Incandescent bulb for motion picture projectors and the like



Oct. 24, 1944.

S. PARISH INGANDESCENT BULB FOR MOTION PICTURE PROJECTORS AND THE LIKE Filed Sept. 10, 1942 II! II! II! It ll ll w 1 1, u 0

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INVENTOR SCOTT PARISH.

BY f ATTORNEYS.

Patented Oct. 24, 1944 INCANDESCENT BULB FOR MOTION PIC- TUBE PROJECTORS AND THE LIKE Scottlarish, Cleveland, Ohio Application September 10, 1942, Serial No. 457,841

4 Claims.

This invention relates to motion picture pro- :Iectors and the like, but has reference more particularly to devices for projecting the light through the film and to reflectors associated therewith.

In my United States Letters Patent No. 2,298,308, of which the present application is a continuation in part, I have described and claimed the combination of a tubular bulb having a light source therein, and a member having a portion in the form of a hollow spherical reflector having spaced openings through which the bulb extends and a third opening having an axis normal to that of said first-named openings, said reflector portion adapted to reflect rays from said light source through said third opening.

The present application is directed to a special form of incandescent bulb, in which I have combined the motions of the bulb and separate reflector of the aforesaid patent, and by the use of which certain highly advantageous results are secured.

The invention can best be understood by reference to the accompanying drawing, wherein,

Fig. 1 is a cross-sectional view of a typical form of motion picture projector lamp housing, having the incandescent bulb of the present invention incorporated therein;

Fig. 2 is a front elevation of the bulb, and

Fig. 3 is a view partly in section and partly in side elevation of the bulb shown in Fig. 2.

Referring more particularly to the drawing, it will be seen that a typical lamp housing of a motion picture projector, such, for example, as an 8 mm. projector designed for home use, comprises a housing proper I, and a casting 2 in which is mounted the condensing lens 3.

Disposed within the housing I is the incandescent bulb of the present invention, which comprises a base t and a portion 5 in the form of a truncated hollow sphere, the planes of truncation being indicated by the dotted lines, and tubular portions 5 and 1 extending from said sphere at the planes of truncation. The tubular portion 6 connects the spherical portion 5 of the bulb with the base 4, and the tubular portion 1, which has its axis in alignment with the axis of the tubular portion 6, terminates in a rounded tip 8.

The internal surface 9 of the portion 5 of the bulb is coated with a reflecting material, such as silver, or other metallic plating, to provide a reflector for the light rays emanating from the filaments ill, which are disposed at substantially the center of the spherical portion of the bulb.

The portion 5 of the bulb is flattened as at II to provide a circular window for the reflected light rays, the window it being left uncoated. The axis of the window I! is normal to the axis of the tubular portions of the bulb. If desired, the outer surface of the bulb portion 5 may be coated with a reflecting material instead of the inner surface thereof.

In use, light rays from the filaments Ill will be reflected by the coated surface of the portion 5 of the bulb, and the rays will then pass through the condensing lens 3 and thence to reflectors (not shown), but.usually forming a part of the projector.

Since the entire outer surface of the bulb is exposed, the bulb may be efllciently ventilated by directing an air blast against the reflector portion thereof, and dispensing with the need for metallic air deflectors and like elements usually required to ventilate the bulb.

By mirroring the tubular portions of the bulb, as well as the spherical portion, the light rays from the filament which would otherwise escape through such tubular portions can be utilized to augment the illumination provided, by the spherican be obviated.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the embodiments herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. An incandescent bulb for motion picture projectors and the like, having a portion in the form of a double truncated hollow mirrored sphere, having a flattened portion which is left unmlrrored, tubular mirrored portions extending from said sphere at the planes of truncation, and a filament in said first-named portion of the bulb.

2. An incandescent bulb for motion picture projectors and the like, having a portion in the form of a truncated hollow mirrored sphere having a flattened circular portion which is left unmirrored and the axis of which intersects substantially the center of said sphere, said flattened portion lying in a plane normal to the plane of truncation of said sphere, and said sphere having a filament therein.

3. An incandescent bulb for motion picture projectors and the like, having a portion in the form of a truncated hollow mirrored sphere, having a flattened portion which is left unmirrored, and a tubular mirrored portion extending from said sphere at the plane oi truncation, said tubular portion having its axis extending substantial- 1y parallel with the plane of said flattened portion.

4. An incandescent bulb for motion picture 10 SCOIT PARISH. 

